Blockquote
Ive Sketched out my concept, the machine has six heads so it is possible to isolate one head for trialing.
Blockquote
In answer to your question.
The initial registration is manually set up on the head to be as close as possible to the previous registration mark on the material to be printed, with the adjusters set at mid position; this is achieved by disengaging the drive from the print roller and moving it to a position that is within a tolerance of +/- 10mm manually.
Then the machine should make the required adjustments on a dynamic basis whilst it is running.
The only way i can see this working is to somehow generate a pre-defined cross hair on the camera image(fixed reference point)too which a detected image can be aligned too whilst the machine is running thus providing outputs for the Horizontal and vertical compensators to align or superimpose both crosses on top of each other.
I hope this makes things clearer
That looks tricky. I'd be more inclined to work with the manufacturer to figure out why the existing hardware isn't taking care of this.
If you are determined to home-brew it, I would expect that you will need something fast and with plenty of memory for the image processing, Teensy 4.1 perhaps. It's tempting to use a Pi, but you have to find a way to make it control the hardware on time, which it won't out of the box.
Would the Teensys need to communicate? I'm wondering whether adjusting one head would have an impact on the others.
Blockquote
I am an engineer, I’ve tried to avoid a protracted explanation regarding the old system but it’s based around a PCD 892 - 128k x8 flash memory card running DOS. On an industrial frame PC running a 486 DX with 4Mb ram.
The Image heads are of the same era. The main problem was, it is now unsupported, But I managed to rebuild the whole system and get it running.
Then once running found that the image detection was at best very poor. The current project we are running uses a Hologram that is dry peel laminated and requires sensor registration marks printed in black so it can be aligned for 1st die cutting then, once processed these registration marks are used by an automated lamination machine to laminate the holographic patch to a card.
The old registration system cannot see the holographic registration marks!!!!!
The image processing timing would be - 545mm -700mm is the normal repeat so 1 registration mark per repeat normal running speed of the machine is 30mtrs per minute.
I see no problem with each head running independently
Oh my!
I guess home-brew is the way then. I'm not sure about needing a cross in the camera's image. I'd expect that the cameras can be at a fixed location and will expect the registration mark to be underneath them at a time determined by the repeat size. How accurate does it have to be and what does that tell you about how often you need to get an image from the camera?
Blockquote
Thank you for having some understanding in this…..
The reason I suggested that a pre-defined cross is laid in, is so it might be possible to use the encoder data to assist with the detection of the collected registration mark…..
Don’t forget that the registration mark is being detected from one head behind.
I am happy if you are interested to discuss this fully or even show you the setup on site. There is a large commercial application for this if we can make something work.
I wonder if a camera is the best solution - it looks like Pixy is sixty frames a second, so there will be nearly a centimeter of movement during a frame. I'd be inclined to look at other similar systems and see how they do it.
Blockquote
I will look under the bonnet of the old system; I know it uses a scope Gate Board see attached images. There is a possibility of generating a strobe to flash once every repeat to freeze the registration mark. I have been in the print industry many years, I know years ago we were using a motorized light table bed to punch negatives which a CCD. It had a predefined cross hair and the table moved the negative which had a reverse cross hair to punch it for platemaking registration. A very similar system???
